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Cheap Web Hosting: The Difference between Static IPs and
Shared IPs
One term you see tossed around a lot in cheap web hosting
is IP addresses. There are basically two types of IP addresses:
static and shared. Before the difference between the two
is discussed, the definition of an IP must be discussed.
When someone types in the address: www.yourdomain.com
that name is translated into numbers (called an IP address)
and then the computer is directed to that IP address which
is the web site. Every web site on the internet is found
not by its domain name but by its IP address. IP addresses
are in the format similar to 191.168.0.1, four discreet
blocks separated by periods. You can reach a site by typing
in the IP address alone and that will take you directly
to the site. For example www.example.com resolves (turns
into) 64.191.62.75. So if you type in 64.191.62.75 directly
into the address bar of your browser you will arrive the
home page of this website.
Now every single website has an IP address specifically
allocated to it. For example, every single website on this
server does not use different IP addresses. If every site
used a different IP address there could potentially could
be a problem with running out of IP addresses. (Fortunately
this is not a problem and is going to be resolved when a
new IP address standard is fully adopted). A lot of the
sites on this server, and other servers on the internet,
use one IP address for multiple sites. Using more than one
IP address frees up IP address which are a limited resource.
Basically what happens is that when site is resolved into
the IP address, the person looking for site arrives at the
server; the server then realizes that the person is looking
for site and sends that page to the person requesting it.
The server basically steps in and does a millisecond of
work and saves an IP address. Using more than one site on
an IP address is called sharing IPs or a Shared IP address.
If a site has its own IP address, and shares with no one
else, it is called a Static IP address. You can always reach
a site which has a static IP address by using its IP address
alone, but you can't reach a site using a shared IP address
by typing in the IP address alone because when you type
in a shared IP address you arrive at the server but the
server doesn't know which site you want because you haven't
told it which domain name you want. So looking at our example
above, we typed in 64.191.62.75 and arrived at www.example.com
we know that only www.example.com uses this address because
we can get to site without typing in a domain name and thus
it must be a static IP address. But why do you need a static
IP address?
The main reason for having a static IP address is that
you can only use SSL encryption (the stuff that makes e-commerce
happen) on a static IP address. In order for a person to
transmit sensitive data over the internet at times this
data must be encrypted to prevent someone from intercepting
the information. You can only use this encryption (called
SSL) when the web site has its own IP address (static IP).
It doesn't work on a shared IP. So when www.example.com
takes in order with a person's credit card it needs to encrypt
this data and it uses SSL with its static IP. Another reason
for having a static IP address is that if a web site wanted
to have anonymous ftp transfers (basically where anyone
can download files off a site) the site needs to have a
static IP address to handle the anonymous ftp transfer.
Other than these two reasons there is no need for a site
to have its own IP ddress.
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